The purpose of this work is to identify the toxic factors of streptococci, especially Group A, that play a role in streptococcal pathogenesis. The major emphais is to purify and characterize the hemolysin, streptolysin S (SLS). Using the cellular precursor to SLS, the hemolytic moiety is to be purified and used to serologically assess host response to this toxin in acute and chronic streptococcal disease such as glomerulonephritis. Enzymatic methods to degrade Group B streptococci are being developed to better study its toxins (hemolysin(s) apparently different than SLS). Various toxins, such as erythrogenic toxin, and cell components such as lipoteichoic acid, are being compared between Groups A, B, C, and G streptococci to determine potential relationships in disease production. The cell walls of Group A streptococci are being studied in the production. The cell walls of Group A streptococci are being studied in the production of arthritis to study the genetic determinants of host responses.